Sinployea aunuuana Solem

Aunuu Sinployea Snail (Sinployea aunuuana)

This species, which is restricted to the small island of ‘Aunu’u offshore Tutuila’s east coast in the American part of Samoa, was described in the year 1983.

The shell reaches an average size of 0,28 cm in diameter. [1]

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The island of ‘Aunu’u was investigated in intensive field studies in the year 2001, when the island was found to be infested with two alien snail species: the Two-toned Gulella (Huttonella bicolor (Hutton)), and the West African Streptostele Snail (Streptostele musaecola (Morelet)); both are known to be invasive, mainly snail-eating species, and both are found on many Pacific islands now.

The Aunuu Sinployea Snail was not found in 2001, and is now considered most likely extinct. [2]

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References:

[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part II, Families Punctidae and Charopidae, Zoogeography. Field Museum of Natural History Chicago, Illinois 1983
[2] Robert H. Cowie; Rebecca J. Rundell: The Land Snails of a small tropical island, Aunu’u, American Samoa. Pacific Science 56(2): 143-147. 2002

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Powelliphanta augusta Walker, Trewick & Barker

Mount Augustus Predatory Snail (Powelliphanta augusta)

This species was described in 2008, it was until then known under the tag name Powelliphanta “Augustus”. [1]

The Mount Augustus Predatory Snail was discovered in 1996 at the ridgeline of Mt. Augustus northeast of Westport.

This locality was subsequently destroyed by mining operations, and about 6000 snails were taken from the locality in 2007 to protect them from the mine development. The ca. 4000 snails that were released to nearby sites showed an alarmingly high mortality rate, and 800 were even killed accidently by the Department of Conservation in a fridge during a captive program in 2011.

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References:

[1] Steven A. Trewick; Kath J. Walker; Corina J. Jordan: Taxonomic and conservation status of a newly discovered giant landsnail from Mount Augustus, New Zealand. Conservation Genetics 9(6): 1563-1575. 2008

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Photo: K. J. Walker

(under creative commons license (4.0))
http://creativecommons.org/licenses/by/4.0

Orobophana musiva (Gould)

Mosaic Orobophana Snail (Orobophana musiva)

This species was described in 1847, it is found in Fiji, in Samoa, and obviously in Tuvalu as well.

The Mosaic Orobophana Snail is found under decaying vegetation at low elevations, very often near the coast.

It is a very small species, the shells reach heights of only about 0,2 cm, they vary in color from several shades of yellow and orange to reddish-brown.

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References:

[1] Robert H. Cowie; Rebecca J. Rundell: The land snails of a small tropical island, Aunu’u, American Samoa. Pacific Science 56(2): 143-147. 2002

Ostodes exasperatus Girardi

Large Ostodes Snail (Ostodes exasperatus)

This species was described in 1978.

The species is known from the islands of Savai’i and ‘Upolu, however, these two populations differ from each other in so far that the males from ‘Upolu are larger than the females, while the situation is reversed in Savai’i.

The shells reach a height of about 0,9 to 1,3 cm and a width of up to 1,3 cm. [1][2]

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References:

[1] E. L. Girardi: The Samoan land snail genus Ostodes (Mollusca: Prosobranchia: Poteriidae). The Veliger 20(3): 191-246. 1978
[2] Robert H. Cowie: Catalog of the nonmarine snails and slugs of the Samoan Islands. Bishop Museum Bulletin in Zoology 3. 1998

Powelliphanta spedeni (Powell)

Speden’s Predatory Snail (Powelliphanta spedeni)

This species, described in 1932, is endemic to the South Island of New Zealand.

The shell reaches a size of about 4 cm in diameter.

This species is thought to contain two subspecies, the nominate, Powelliphanta spedeni ssp. spedeni (Powell), and Powelliphanta spedeni ssp. lateumbilicata (Powell).

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Powelliphanta spedeni ssp. lateumbilicata

Photo: D. Coetzee

(public domain)

Minidonta extraria Cooke & Solem

Strange Disc Snail (Minidonta extraria)

This species was described in the year 1976 from three specimens, of which one was found on the island of Akamaru, one on the island of Mangareva, and one on the island of Taravai.

The shells reach an average size of 0,29 cm in diameter.

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References:

[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976
[2] Ahmed Abdou; Philippe Bouchet: Nouveaux gastéropodes Endodontidae et Punctidae (Mollusca, Pulmonata) récemment éteints da l’archipel des Gambier (Polynésie). Zoosystema 22(4): 689-707. 2000

Justin Gerlach: Partula – Icons of Evolution

Justin Gerlach: Partula – Icons of Evolution

The genus Partula, extremely rich in Polynesian species, will soon get it’s newest monograph (I’m not sure, but it may be the first monograph at all).

The book, written by Justin Gerlach and named “Partula – Icons of Evolution”, is nearly ready to be published, but the project can still be supported.:

https://www.kickstarter.com/projects/507116283/partula-icons-of-evolution

 

Endodonta apiculata Ancey

Pointed Disc Snail (Endodonta apiculata)

The Pointed Disc Snail, which was restricted to the island of Kaua’i, Hawaiian Islands, was described in the year 1889.

The shells of this species reached an average size of 0,6 cm in diameter. [1]

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The genus Endodonta contains a little more than 10 species, all, except probably for one, are now obviously extinct.

The destruction of large areas of the native lowland habitats led to their extinction, and introduced invasive species, especially several aggressive ant species (for example the Red Fire Ant (Solenopsis invicta Buren) or the Little Fire Ant (Wasmannia auropunctata (Roger))) are a very serious threat to the last remaining endemic snail species, and are blamed for the extinction of many island endemic species. [2]

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References:

[1] Alan Solem: Endodontoid land snails from Pacific Islands (Mollusca: Pulmonata: Sigmurethra). Part I, Family Endodontidae. Field Museum of Natural History Chicago, Illinois 1976
[2] Norine W. Yeung; Kenneth A. Hayes: Update on the status of the remaining Hawaiian land snail species Part 4: Punctidae and Endodontidae. 2016

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edited: 23.03.2017

Partula otaheitana (Bruguière)

Otaheite Tree Snail (Partula otaheitana)

The Otaheite Tree-Snail, whose name refers to it as being endemic to the island of Tahiti (Otaheite is an old name of the island), was described in 1792.

This species is nowadays highly threatened with extinction, yet somehow managed to withstand the introduction of the Rosy Wolf Snail (Euglandia rosea (Férussac)) to Polynesia, that had cost the lives of so many other endemic snail species.

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The Otaheite Tree-Snail is split into four so called anatomical forms, which overlap or are linked to each other by intermediate forms, and which are each restricted to certain parts of Tahiti. They may or may not be treated as subspecies, and are named as Partula otaheitana ssp. crassa Garrett (in the western part of Tahiti nui), Partula otaheitana ssp. otaheitana Bruguière (in the northern part of Tahiti nui), Partula otaheitana ssp. rubescens Reeve (in the eastern part of Tahiti nui as well the northern part of Tahiti iti), and finally Partula otaheitana ssp. sinistrorsa Garrett (in the largest part of Tahiti nui, including the center of the island and the southern part, as well as the most parts of Tahiti iti).

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References:

[1] Justin Gerlach: Icons of Evolution: Pacific Island tree-snails, family Partulida, Phelsuma Press, Cambridge U.K. 2016

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Photo: Antonio Machado; by courtesy of Antonio Machado

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edited: 31.08.2017